Identification of brain structures and networks encoding pain, hyperalgesia, pain control and sympathetic function acutely after stroke. A voxel-based lesion-behavior – network mapping study of acute stroke patients

对大脑中疼痛、痛觉过敏和疼痛控制机制的编码还不完全清楚。交感神经系统功能的编码也是如此。功能磁共振成像(FMRI)研究了健康受试者在重复的短时间疼痛刺激后的大脑激活，其结果的特异性最近受到了挑战，因为短期疼痛刺激的非生理性突显。该项目将通过研究中风后2-7天中枢重组过程发生前的临床表现型来研究感觉(包括痛觉、痛觉过敏、通过定量心理物理学评估的疼痛控制)和交感障碍作为临床表型，从而克服这一缺点。通过基于体素的病变行为映射(VLBM)，这种行为将与大约200名患者的结构性磁共振成像中的大脑病变相关联。由于最初描述的VLBM可能不足以检测单独的大脑损伤，而单个大脑损伤单独负责复杂的感觉行为(例如，痛觉过敏或疼痛控制)，因此分析将扩展到“行为-大脑网络”映射。这将通过使用主要来自AgeGain项目(Mainz Data)的匹配正常受试者的数据集来实现，该项目提供功能连接数据，并将使我们能够评估作为种子的个别大脑局灶性病变对大脑网络的影响。来自个人的连接数据将在第二步中重叠。我们预计，与不同表型相关的受影响网络的重叠程度高于脑局灶性病变本身。另一种方法是评估局灶性脑损伤对预定义的静息状态功能磁共振成像(RS-fMRI)网络的影响。RS-fMRI扫描将与结构扫描一起获得。在这个项目的最后，我们将描述负责对疼痛、痛觉过敏、疼痛控制和植物行为进行编码的大脑网络。此外，这项研究的结果可能成为一项设想的纵向研究的基础，揭示大脑网络损伤的模式，这些损伤可能会导致中风后几个月的慢性中风后疼痛，原因是大脑重组不适应。

The encoding of pain, hyperalgesia and pain control mechanisms in the brain is incompletely understood. The same applies for encoding of sympathetic nervous system function. The specificity of results of functional MRI (fMRI) studies, which investigated brain activation after repetitive short pain stimuli in healthy subjects, was recently challenged because of the non-physiological salience of the short-lasting pain stimuli. This project will overcome this shortcoming by investigating sensory (including pain perception, hyperalgesia, pain control assessed by quantitative psychophysics) and sympathetic dysfunction as a clinical phenotype 2-7 days after stroke before central reorganization processes take place. The behavior will be correlated to brain lesions in structural MRIs of ~200 patients by voxel-based lesion-behavior mapping (VLBM). Since the originally described VLBM might be not sufficient to detect single brain lesions, which alone are responsible for complex sensory behavior (e.g. hyperalgesia or pain control), the analysis will be extended to “behavioral–brain network” mapping. This will be achieved by making use of datasets of matched normal subjects mainly from the AgeGain project (Mainz data), which provides functional connectivity data and will allow us to assess the impact of individual focal brain lesions as seeds on brain networks. The connectivity data from individuals will be overlapped in a second step. We expect a higher overlap of the affected networks associated with a distinct phenotype than of the focal brain lesions themselves. Another approach will be to assess the impact of focal brain lesions on predefined resting state functional MRI connectivity (rs-fMRI) networks. The rs-fMRI scans will be obtained together with the structural scans. At the end of this project we will describe the brain networks that are responsible for encoding of pain, hyperalgesia, pain control and vegetative behavior. Moreover, the results of this study might become the basis for an envisaged longitudinal study uncovering the patterns of brain network lesions which can lead to chronic post-stroke pain months after stroke due to maladaptive brain reorganization.